Contents

Abstract

Sickle cell disease is an inherited disorder of haemoglobin, the protein
in red blood cells that carries oxygen. In this condition, an abnormal
haemoglobin S from one parent is combined with another abnormal
haemoglobin from the other parent. Haemoglobin S inherited from both
parents (genotype HbSS), described as sickle cell anaemia is the most
common form.

Depending on the institutional policy, blood transfusion can be given at
intervals to a pregnant HbSS woman with relatively few or no symptoms to
improve the oxygen carrying capacity of blood by increasing haemoglobin
blood concentration and lowering haemoglobin S levels; or only when
indicated by the development of medical or pregnancy complications.
Giving blood at frequent intervals carries the risks of blood-borne
infections and excessive levels of iron.

This review set out to determine whether giving blood at intervals
before serious complications occur compared with giving blood only when
medically indicated makes a difference to the health of the mother and
her baby. The review authors included two controlled trials that
randomised 98 women with sickle cell anaemia (haemoglobin SS) before 28
weeks of gestation to one of the two blood transfusion policies. The two
trials were of low quality. One trial (72 women) indicated no difference
in severe ill health and death of the mother or newborn. There was no
difference in the risk of delayed blood transfusion reaction. The two
trials suggested giving blood at frequent intervals marginally reduced
the risk of pain crisis, with a large degree of uncertainty about the
size of the effect, compared with giving blood only when medically
indicated. Blood transfusion was delivered at a ratio of four or five to
one for prophylactic versus selective blood transfusion, respectively.

Overall, available evidence on this subject is insufficient to advocate
for a change in clinical practice and policy.